Secondary effluent reclamation: combination of pre-treatment and disinfection technologies

2008 ◽  
Vol 57 (12) ◽  
pp. 1963-1968 ◽  
Author(s):  
L. Alcalde ◽  
M. Folch ◽  
J. C. Tapias ◽  
F. Martínez ◽  
S. Enguídanos ◽  
...  

A study was carried out to evaluate the efficiency of secondary effluent additional treatment, using a combination of pre-treatments (ring filter, physico-chemical and infiltration-percolation) followed by disinfection methods (chlorine dioxide, peracetic acid and ultraviolet light). Three different indicator microorganisms were determined: E. coli, total coliforms and somatic bacteriophages. The results show better efficiency of physico-chemical and infiltration-percolation processes. Bacteriophages were eliminated to a lesser extent than bacterial indicators in all the treatment systems. Chlorine dioxide and peracetic acid seems to be more efficient in disinfection than ultraviolet light when a ring filter is the pre-treatment used. For the same doses and contact times, the efficiency of the disinfection methods is higher when the pre-treatment used is the physico-chemical or the infiltration-percolation system. The final effluent quality from the physico-chemical treatment train and the infiltration-percolation treatment train, followed by the disinfectants, achieves an E. coli content that allows the reuse in most of the uses described in the Spanish legislation for wastewater reuse.

2013 ◽  
Vol 68 (12) ◽  
pp. 2638-2644 ◽  
Author(s):  
M. Antonelli ◽  
A. Turolla ◽  
V. Mezzanotte ◽  
C. Nurizzo

The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent.


Author(s):  
Henry Jacques Matita Bomoi ◽  
Gédéon Ngiala Bongo ◽  
Pius Tshimankinda Mpiana ◽  
Kola Nsimba ◽  
Nzau Matiaba ◽  
...  

Water pollution is currently at the top of the environmental agenda. In this study, the main objectives were (i) to assess the physicochemical and bacteriological quality of well and borehole water found in the vicinity of the University of Kinshasa and (ii) to assess the sensitivity of Escherichia coli and Enterococci strains isolated from various selected water points to disinfectants used at the industrial scale (Chlorine and chlorine dioxide) or in the household (Aquatabs) for the microbiological treatment of water. Three sites having wells or boreholes were chosen for sample collection, namely: The University of Kinshasa and its vicinity (Kindele and Kemi districts). The Physico-chemical parameters were determined in situ and then in the laboratory; and concerned the following indicators: pH, conductivity and turbidity. Moreover, the bacteriological quality was assessed by detecting the presence of faecal pollution indicator bacteria (E. coli and Enterococcus sp). The susceptibility of E. coli and Enterococcus sp strains to antimicrobials generally used for the microbiological treatment of drinking water was assessed by the dilution method on agar medium. The physico-chemical analyses showed that: (i) acid pH values in the different water points under study ranging from 6.3-6.5, (ii) conductivity and turbidity values range between 28.5 and 146 NTU. The bacteriological analyses showed that the Kemi district was the only water point which exhibited contamination with fecal pollution indicator bacteria. The strains of Enterococci and E. coli isolated from that well were highly sensitive to chlorine dioxide and Aquatabs and less sensitive to chlorine while the strains of E. coli are highly sensitive to chlorine dioxide and Aquatabs compared to the strains of Enterococci. In conclusion, we can recommend to these populations, the use of these compounds for water treatment precisely Aquatabs for household.


2007 ◽  
Vol 55 (7) ◽  
pp. 149-154 ◽  
Author(s):  
L. Alcalde ◽  
M. Folch ◽  
J.C. Tapias ◽  
E. Huertas ◽  
A. Torrens ◽  
...  

The demands established in the rules and regulations by the administration in Catalonia seem to exclude small communities from wastewater reclamation and reuse, due to the comparatively high costs associated with the practice at small scale. In the framework of the DRAC project (Demonstration on Wastewater Reclamation and Reuse in Catalonia) two different pre-treatment systems, one extensive (infiltration–percolation) and another intensive (ring filter), each one followed by chlorine dioxide disinfection, were tested in order to be applied for small communities wastewater reclamation and reuse. The results of this study show that infiltration–percolation systems remove very efficiently physico-chemical contaminants and microorganisms. The ring filter system does not show a significant removal rate of contaminants. The use of infiltration–percolation as a pre-treatment for advanced chemical disinfection allows reducing the dose of disinfectant and the contact time needed to achieve a specific water quality, and diminishes disinfection by-products (DBPs) generation. Therefore, this reclamation line is suitable for small communities due to its efficiency and low cost. However, further studies are needed in relation to the removal mechanisms of microorganisms, organic compounds in IP systems and the possible DBPs formation using chlorine dioxide.


2019 ◽  
Vol 5 (8) ◽  
pp. 1453-1463 ◽  
Author(s):  
Abdulrahman H. Hassaballah ◽  
Jeremy Nyitrai ◽  
Christine H. Hart ◽  
Ning Dai ◽  
Lauren M. Sassoubre

At the pilot-scale, peracetic acid effectively inactivates fecal coliforms,E. coliandEnterococcusspp. in secondary and tertiary treated wastewater. The addition of UV to PAA treatment increases inactivation of somatic coliphage.


2011 ◽  
Vol 71-78 ◽  
pp. 2792-2796
Author(s):  
Li Hua Cheng ◽  
Ai Hua He ◽  
Xue Jun Bi ◽  
Qi Wang

Due to increasing water scarcity, reclamation and reuse of the secondary effluent of wastewater treatment plant are widely concerned in many countries. Before reuse, the residual contaminant in the secondary effluent should be further removed to guarantee safe reuse. Coagulation/sedimentation and subsequent chlorine dioxide(ClO2) disinfection was adopted for tertiary treatment of secondary effluent. Selection of coagulant and optimization of tertiary treatment parameters were performed in this study. The results showed that coagulation could remove turbidity and total phosphours(TP) effectively. Polyaluminium chloride(PAC) was the most suitable coagulant. The optimal coagulation condition was as follows: PAC dosage of 10mg/L(measured as Al3+), reaction time of 20 min, settling time of 40 min, in this case, the average removal rate of turbidity, color, UV254, TP and TOC could reach to 58.2%, 22.8%, 18.2%, 60.6% and 22.2%, respectively. ClO2could inactive bacteria andE. colieffectively. ClO2could further remove UV254, color and TOC. In case of ClO2dosage of 5mg/L, the sterilization efficiency could reach 100%, and the removal rate of UV254, color and TOC was higher than 25%, 70% and 25%, respectively. In the optimal condition, the removal efficiency of residual contaminant by the combination process was as follows: UV254of 45.9%, color of 76.5%, TOC of 66.7%, turbidity of 61.9% and TP of 96.3%.


2003 ◽  
Vol 3 (4) ◽  
pp. 269-275 ◽  
Author(s):  
V. Mezzanotte ◽  
M. Antonelli ◽  
A. Azzellino ◽  
S. Citterio ◽  
C. Nurizzo

The paper summarises - in terms of bacterial removal and re-growth - the results of a pilot scale study performed on a continuous flow pilot plant, using peracetic acid (PAA) as disinfecting agent. Trials were carried out with increasing doses and contact times (6, 12, 18, 36, 42, 54 min). The paper reports data deriving from the only doses (15 and 25 mg L-1) which were able to ensure the respect of the limits for agricultural re-use, according to Italian law. Disinfection efficiency was comparable for E. coli, TC and FC, and lower for total heterotrophic bacteria (THB), and clearly grew with increasing Cát values. The effect of contact time was greater at the lower doses. Microbial counts, performed by both traditional methods and flow cytometry, immediately and 6 hours after the sample collection (PAA was previously inactivated by sodium thiosulphate and bovine catalase), showed that no appreciable re-growth took place after 6 hours for coliform group bacteria. THB formed a slightly lower number of colonies immediately after collection than after 6 hours. The slight variations observed after 6 hours were the result of the recovered ability of forming colonies and of the lysis of some of the residual bacteria, as it was shown by flow cytometry.


1989 ◽  
Vol 21 (3) ◽  
pp. 203-206 ◽  
Author(s):  
M. G. C. Baldry ◽  
M. S. French

Novel products based on peracetic acid (PAA) have recently been developed for the disinfection of sewage and sewage effluents. The efficacy of such products has been assessed under both laboratory and operational conditions. Comparative laboratory studies of the effects of peracetic acid, chlorine dioxide and chlorine on indicator bacteria in secondary sewage effluent have shown peracetic acid to be a viable alternative to these halogen biocides. In a trial carried out at two small rural works, PAA was dosed into secondary effluent from either an activated sludge plant or a percolating filter bed prior to tertiary lagoon treatment. LOW levels of PAA greatly enhanced the natural decline in coliform levels across the lagoon, enabling much lower concentrations of bacteria to be discharged into the receiving streams. In another trial, secondary effluent from an activated sludge plant was treated before discharge into a stream leading to the sea. Coliform concentrations were greatly reduced along the watercourse downstream from the plant.


2019 ◽  
Vol 2 (2) ◽  
pp. 397-408
Author(s):  
Tong Thi Anh Ngoc ◽  
Phan Thi Thanh Que

Minimally processed fruits and vegetables are economically important commodities due to convenience, and healthiness, etc. These commodities are susceptible and shelf life limited as cut surfaces of vegetable result in microbiological and physiological spoilage. To extend the shelf life of Asian spinach vegetables, different washing treatments (i.e. tap water, chlorine dioxide, and peracetic acid) and packaging materials (i.e. Polypropylene-PP, High Density Polyethylene-HDPE and Low Density Polyethylene-LDPE) were evaluated in the study. The results obtained show that washing treatment of the Asian spinach with peracetic acid solution of 100 ppm for five minutes was effective due to reduced significantly E. coli and Coliforms counts. The Asian spinach was packed in HDPE material might optimally prolong the shelf life up to 7 days at 10±1oC.


2018 ◽  
Vol 36 (No. 5) ◽  
pp. 378-385
Author(s):  
Vytautas Januskevicius ◽  
Grazina Januskeviciene ◽  
Gintare Zaborskiene

The aim of this study was to investigate the possible harmful effect of Sarcocystis parasites on bovine diaphragm meat quality. Meat samples were collected from 120 bulls aged 20–24 months. Meat quality was investigated using microbiological and physico-chemical (RP-HPLC, GC) methods 48 hours after slaughter. Sarcocystis infection was associated with increased fat content, lightness L* and drip loss, and decreased ash and protein percentages. Infection also had a significant effect on the amount of amino acids (AAs), which slowly decreased as the number of sarcocysts increased. The total amount of AAs correlated with glutamic acid content (R = 0.966, P &lt; 0.05). Heavily infected samples contained significantly lower amounts of putrescine, histamine, spermine and spermidine (P &lt; 0.05) and<br /> a noticeable increase in the total count of aerobic microorganisms, but no change in the numbers of E. coli and coliform bacteria in comparison with no infected samples. Sarcocysts in beef diaphragms did not cause serious changes in the technological quality of the meat, but the biological quality of infected meat was reduced.  


Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3065
Author(s):  
Juan Lv ◽  
Yan Wang ◽  
Na Li

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.


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